Groundwater Discharge

Managing construction dewatering and discharge

LOTT occasionally receives requests to discharge groundwater into the regional wastewater system. These requests are typically related to dewatering a construction site or cleaning up contaminated soil and/or water as part of site development. LOTT may accept these discharges of groundwater as long as they are within discharge limits specified in LOTT's Pretreatment Regulations. These discharges must be pre-approved in writing, following this process:

  1. Applicants must complete and return the Groundwater Discharge Application; once a completed application is submitted, it will take approximately two weeks for processing.
  2. Applicants will receive a final Discharge Authorization letter specifying volume limits and requiring treatment of contaminants.

While LOTT may accept groundwater, the associated sediments and potential contaminants must be kept out of the sewer system. Groundwater that is known or suspected to be contaminated must be adequately treated to remove contaminants prior to discharge.

These discharge requirements are in place to prevent unpermitted discharges of groundwater from diluting wastewater and affecting LOTT’s ability to treat it. They also prevent contaminants from polluted sites from entering LOTT’s treatment plant, and possibly Budd Inlet.

Groundwater Discharge Guide (PDF)

Groundwater Discharge Application (PDF)

Pretreatment Regulations (PDF)